Ploughing came to a halt due to a breakdown.
The unloading valve plug leaked again. The fix in service was to replace the plug with the next size up, but seeing as you can't get the plugs anymore, and I didn't fancy paying £30 (mates' rates) to have a new one made, I have tried a different solution.
I extracted the old plug, which despite the fact that it was leaking, was still a very tight interference fit, cleaned it and the bore thoroughly, then applied a thin film of Loctite 603 to the plug and bore. The very helpful technical team at Henkel explained that 603 is designed for just this purpose.
The hydraulic lid is still off as I wait for the 603 to cure, so I don't know yet if the problem is solved. The ultimate test will be when the oil is up to temperature an hour into ploughing. With the oil hot, the leak was pretty significant - the draft control wouldn't regulate the depth correctly and the hydraulics were only just able to raise the plough at the end of the furrow.
If it does work, and the technician said he would be amazed if it didn't, I am hoping that the unloading valve doesn't stick at any point in the future, as removing the plug won't be an easy option.
On this last point, has anyone tried using a telescopic magnetic retrieval tool of a small enough diameter to pull the stem of the unloading valve if it sticks in the lowering position?
Hoping to get back to the tractor at the weekend to reassemble. Fingers crossed the above approach works.
Best, Adrian.
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